/*

 *   SONEWS News Server

 *   see AUTHORS for the list of contributors

 *

 *   This program is free software: you can redistribute it and/or modify

 *   it under the terms of the GNU General Public License as published by

 *   the Free Software Foundation, either version 3 of the License, or

 *   (at your option) any later version.

 *

 *   This program is distributed in the hope that it will be useful,

 *   but WITHOUT ANY WARRANTY; without even the implied warranty of

 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *   GNU General Public License for more details.

 *

 *   You should have received a copy of the GNU General Public License

 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

package org.sonews.daemon;

import java.sql.SQLException;

import java.util.Map;

/**

 * Will force all other threads to shutdown cleanly.

 * @author Christian Lins

 * @since sonews/0.5.0

 */

class ShutdownHook extends Thread

{

  /**

   * Called when the JVM exits.

   */

  @Override

  public void run()

  {

    System.out.println("sonews: Trying to shutdown all threads...");

    Map<Thread, StackTraceElement[]> threadsMap = Thread.getAllStackTraces();

    for(Thread thread : threadsMap.keySet())

    {

      // Interrupt the thread if it's a AbstractDaemon

      AbstractDaemon daemon;

      if(thread instanceof AbstractDaemon && thread.isAlive())

      {

        try

        {

          daemon = (AbstractDaemon)thread;

          daemon.shutdownNow();

        }

        catch(SQLException ex)

        {

          System.out.println("sonews: " + ex);

        }

      }

    }

    for(Thread thread : threadsMap.keySet())

    {

      AbstractDaemon daemon;

      if(thread instanceof AbstractDaemon && thread.isAlive())

      {

        daemon = (AbstractDaemon)thread;

        System.out.println("sonews: Waiting for " + daemon + " to exit...");

        try

        {

          daemon.join(500);

        }

        catch(InterruptedException ex)

        {

          System.out.println(ex.getLocalizedMessage());

        }

      }

    }

    // We have notified all not-sleeping AbstractDaemons of the shutdown;

    // all other threads can be simply purged on VM shutdown

    System.out.println("sonews: Clean shutdown.");

  }

}